Sensor system

ABSTRACT

Disclosed herein is a sensor system that detects a stylus on at least one panel surface having an effective region. The sensor system includes a memory device including computer-executable instructions, and a processor. The processor, when loaded with the computer-executable instructions, performs: and obtaining a position of the stylus and a pen pressure value indicating a pressure applied to a pen tip of the stylus; outputting the position and the pen pressure value to a host processor. In response to the position being outside the effective region, the processor performs processing to conceal from the host processor occurrence of at least one of a pen-down indicating the stylus contacting the panel surface and a pen-up indicating the stylus being removed from the panel surface.

BACKGROUND Technical Field

The present invention relates to a sensor system, and particularly to asensor system for performing pen input by a stylus.

Description of the Related Art

Many recent notebook personal computers have a touch pad or a track pad(hereinafter referred to collectively as a “touch pad”). A touch padgenerally has a touch panel for receiving input by a finger (hereinafterreferred to as “touch input”) and a button function for realizing afunction equivalent to a right click function or a left click functionof a mouse device. A touch pad is classified into either a discrete typeor a non-discrete type depending on whether or not the touch panel andthe button function are provided by separate mechanisms.

The discrete type touch pad has a dedicated button for click operationseparately from the touch panel. On the other hand, the non-discretetype touch pad does not have such a dedicated button, but allows clickoperation to be realized by pressing the touch panel. The non-discretetype touch pad can be further divided into two types, that is, a “clickpad” and a “pressure pad” according to specific structures for realizinga click by depressing the touch panel. The click pad is a type of touchpad in which the touch panel is displaced downward when depressed by auser. The click pad includes a click button directly under the touchpanel. On the other hand, the pressure pad is a type of touch pad thatdetects a pressing force applied to the touch panel by a force sensor,and realizes a click by threshold value determination of output of theforce sensor. See, Eliot Graff et al., “Windows Precision TouchpadCollection,” [online], May 2, 2017, Microsoft Corporation [retrieved onJan. 15, 2020], the Internet <URL:https://docs.microsoft.com/en-us/windows-hardware/design/component-guidelines/touchpad-windows-precision-touchpad-collection>,which discloses the above three types of touch pads (the discrete type,the click pad, and the pressure pad).

In addition, attention has recently been directed to a folding typetablet terminal having two screens. In the following, this kind oftablet terminal will be referred to as a “dual screen model.” With theadvent of the dual screen model, development of a technology forenabling the use of both touch input and input by a stylus (hereinafterreferred to as “pen input”) on each of the two screens has beenunderway.

Japanese Patent Laid-Open No. 2019-133487 discloses an example of suchtechnology. As described in Japanese Patent Laid-Open No. 2019-133487, asensor system is provided within the dual screen model, wherein thesensor system includes a first integrated circuit connected to a sensorelectrode group for a first screen, a second integrated circuitconnected to a sensor electrode group for a second screen, and a hostprocessor connected to the first and second integrated circuits. Touchinput and pen input are realized by the sensor system.

When a sensor electrode group is provided on the inside of the panelsurface of a touch panel or the display surface of a display(hereinafter referred to collectively as a “panel surface”) in order torealize pen input and touch input, the sensor electrode group may bedisposed over a region slightly greater than a region corresponding tothe corresponding panel surface (hereinafter referred to as an“effective region”). In that case, a region in which the stylus can bedetected is slightly larger than the effective region. In the following,a region outside the effective region in the region in which the styluscan be detected will be referred to as a “detectable region.” JapanesePatent Laid-Open No. 2000-099260 describes conversion of the position ofa detected stylus to a position within the effective region in a casewhere the position of the detected stylus is within the detectableregion.

BRIEF SUMMARY

Unlike the effective region, the detectable region is a region in whichsliding of a finger or the stylus is not expected. As such, an obstaclesuch as a level difference or a groove may be present in the detectableregion. Because the obstacle is very small, no problem occurs at allwhen touch input is performed by using a relatively thick fingertip, butthe obstacle causes an erroneous operation when pen input is performedby using the pen tip of a relatively thin stylus. That is, when the pentip of the stylus passes the obstacle, a sharp change may occur in a penpressure value detected by the stylus, and an erroneous operation suchas erroneous tapping occurs because this change causes a pen-down notintended by the user.

It is accordingly one aspect of the present invention to provide asensor system that can prevent occurrence of an erroneous operation inpen input.

In addition, as for the dual screen model, there is a desire from usersto draw one line that straddles screens. However, when an obstacle suchas a level difference or a groove or a non-sensitive region in which thestylus cannot be detected is present between the screens, a pen-up notintended by the user occurs at the obstacle or the non-sensitive region.Thus, the line drawing is broken.

It is accordingly another aspect of the present invention to provide asensor system that enables one line to be drawn so as to straddle thescreens of the dual screen model.

According to an aspect of the present invention, there is provided asensor system that detects a stylus on at least one panel surface havingan effective region, the sensor system including an obtaining step ofobtaining a position of the stylus and a pen pressure value indicating apressure applied to a pen tip of the stylus and an output step ofoutputting the position and the pen pressure value obtained in theobtaining step to a host processor. When the position obtained in theobtaining step is outside the effective region, occurrence of at leastone of a pen-down indicating the stylus contacting the panel surface anda pen-up indicating the stylus being detached from the panel surface isconcealed from the host processor.

According to an aspect of the present invention, no pen-down occurs whenthe pen tip is located outside the effective region, and thereforeoccurrence of an erroneous operation in pen input can be prevented. Inaddition, no pen-up occurs when the pen tip is located outside theeffective region, and therefore one line can be drawn so as to straddlethe screens of a dual screen model.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a notebook personal computer accordingto a first embodiment of the present invention;

FIG. 2 is a diagram illustrating an internal configuration of thenotebook personal computer illustrated in FIG. 1 ;

FIGS. 3A and 3B are sectional views of a casing in the vicinity of atouch pad illustrated in FIG. 1 ;

FIG. 4 is a sectional view of a casing constituting a notebook personalcomputer according to a modification of the first embodiment of thepresent invention;

FIG. 5 is a diagram illustrating processing performed by a sensor systemaccording to the background art in relation to the first embodiment ofthe present invention;

FIG. 6A is a diagram illustrating details of “state report processing”performed in step S108 in FIG. 5 , and FIG. 6B is a diagram illustratingdetails of “position etc. report processing” performed in step S111 inFIG. 5 ;

FIG. 7 is a diagram explaining a corresponding position within aneffective region;

FIG. 8 is a diagram illustrating a first example (comparative example1-1) of a result of performing processing according to the backgroundart, wherein such processing is illustrated in FIG. 5 and FIGS. 6A and6B;

FIG. 9 is a diagram illustrating a second example (comparative example1-2) of a result of performing the processing according to thebackground art, wherein such processing is illustrated in FIG. 5 andFIGS. 6A and 6B;

FIG. 10 is a diagram illustrating “position etc. report processing”performed by a sensor system according to the first embodiment of thepresent invention;

FIG. 11 is a diagram illustrating an example (example 1-1) of a resultof performing the position etc. report processing illustrated in FIG. 10;

FIG. 12 is a diagram illustrating position etc. report processingperformed by a sensor system according to a first modification of thefirst embodiment of the present invention;

FIG. 13 is a diagram illustrating an example (example 1-2) of a resultof performing the position etc. report processing illustrated in FIG. 12;

FIG. 14 is a diagram illustrating position etc. report processingperformed by a sensor system according to a second modification of thefirst embodiment of the present invention;

FIG. 15 is a diagram illustrating an example (example 1-3) of a resultof performing the processing according to the present modification,wherein such processing is illustrated in FIG. 14 ;

FIG. 16 is a diagram illustrating state report processing performed by asensor system according to the background art, in relation to a secondembodiment of the present invention;

FIG. 17 is a diagram illustrating a first example (comparative example2-1) of a result of performing the processing according to thebackground art, wherein such processing is illustrated in FIG. 16 ;

FIG. 18 is a diagram illustrating a second example (comparative example2-2) of a result of performing the processing according to thebackground art, wherein such processing is illustrated in FIG. 16 ;

FIG. 19 is a diagram illustrating state report processing performed by asensor system according to the second embodiment of the presentinvention;

FIG. 20 is a diagram illustrating an example (example 2) of a result ofperforming the state report processing according to the presentembodiment, wherein such processing is illustrated in FIG. 19 ;

FIG. 21 is a diagram illustrating a tablet terminal according to a thirdembodiment of the present invention;

FIG. 22 is a diagram illustrating an internal configuration of thetablet terminal illustrated in FIG. 21 ;

FIG. 23 is a diagram explaining problems of the third embodiment of thepresent invention;

FIG. 24 is a diagram illustrating an example (comparative example 3) ofa result of performing processing according to the background art, inrelation to the third embodiment of the present invention;

FIG. 25 is a diagram illustrating state report processing performed by asensor system according to the third embodiment of the presentinvention;

FIG. 26 is a diagram illustrating position etc. report processingperformed by the sensor system according to the third embodiment of thepresent invention;

FIG. 27 is a diagram illustrating an example (example 3) of a result ofperforming the processing according to the third embodiment of thepresent invention, wherein such processing is illustrated in FIG. 25 andFIG. 26 ;

FIG. 28 is a diagram illustrating an example (comparative example 4) ofa result of performing processing according to the background art, inrelation to a fourth embodiment of the present invention;

FIG. 29 is a diagram illustrating state report processing performed by asensor system according to the fourth embodiment of the presentinvention;

FIG. 30 is a diagram illustrating position etc. report processingperformed by the sensor system according to the fourth embodiment of thepresent invention; and

FIG. 31 is a diagram illustrating example (example 4) of a result ofperforming the processing according to the fourth embodiment of thepresent invention, wherein such processing is illustrated in FIG. 29 andFIG. 30 .

DETAILED DESCRIPTION

Embodiments of the present invention will hereinafter be described indetail with reference to the drawings.

First Embodiment

FIG. 1 is a diagram illustrating a notebook personal computer 1according to a first embodiment of the present invention. As illustratedin FIG. 1 , the notebook personal computer 1 includes a casing 2, adisplay 3, a keyboard 4, and a touch pad 5. FIG. 2 is a diagramillustrating an internal configuration of the notebook personal computer1. FIG. 1 illustrates only parts related to the touch pad 5. Asillustrated in FIG. 2 , a host processor 7 is provided within thenotebook personal computer 1.

The host processor 7 is a central processing unit that controls variousparts of the notebook personal computer 1. The host processor 7 plays arole of reading and executing programs stored in a memory, which is notillustrated. The programs executed by the host processor 7 include anoperating system of the notebook personal computer 1, various kinds ofdrawing applications, various kinds of communication programs, and thelike.

The display 3 is an output section for outputting visual informationunder control of the host processor 7. The keyboard 4 and the touch pad5 are input sections that play a role of receiving user input andsupplying the user input to the host processor 7. The notebook personalcomputer 1 is further provided with various kinds of input-outputsections and communicating sections that are possessed by an ordinarycomputer.

FIGS. 3A and 3B are sectional views of the casing 2 in the vicinity ofthe touch pad 5. The touch pad 5 is a click pad described above. Thetouch pad 5 includes a touch panel 5 a, a fulcrum 5 b, and a clickbutton 5 c. The touch pad 5 is embedded as a whole in a rectangularrecessed portion 2 c provided in the casing 2. In an initial state, asurface of the touch panel 5 a is maintained in a state of beingparallel with a surface of the casing 2.

As is understood from FIG. 3A, the touch pad 5 supports both pen inputand touch input described above. Pen input is realized when a userslides a pen tip of a stylus S on the touch panel 5 a, and a sensorcontroller 11 (see FIG. 2 ) to be described later detects a trajectoryof the pen tip of the stylus S. In addition, touch input is realizedwhen the user slides a finger F of the user on the touch panel 5 a, andthe sensor controller 11 (see FIG. 2 ) detects a trajectory of thefinger F.

The fulcrum 5 b and the click button 5 c are each disposed between anundersurface of the touch panel 5 a and a bottom surface of the recessedportion 2 c in a vertical direction. The fulcrum 5 b and the clickbutton 5 c are respectively arranged on a far side and a near side ofthe recessed portion 2 c, in a horizontal direction, as viewed from theuser of the notebook personal computer 1. When the stylus S or thefinger F applies a pressure to a vicinity region of an upper surface ofthe touch panel 5 a, the vicinity region being above the click button 5c, a part of the touch panel 5 a sinks as illustrated in FIG. 3B. Whenan amount of sinking becomes a certain amount or more, the click button5 c is depressed. A click is thus realized. When a part of the touchpanel 5 a sinks, a level difference 5 d occurs between the touch panel 5a and the casing 2, as illustrated in FIG. 3B. Because the leveldifference 5 d is very small, no problem occurs at all when touch inputis performed by a relatively thick finger F, but the level difference 5d causes an erroneous operation described above when pen input isperformed by using the pen tip of a relatively thin stylus S.

FIG. 4 is a sectional view of the casing 2 constituting a notebookpersonal computer 1 a according to a modification of the presentembodiment. The notebook personal computer 1 a according to the presentmodification is different from the notebook personal computer 1according to the present embodiment in that the notebook personalcomputer 1 a has a touch pad 6 as a discrete type or a pressure pad inplace of the touch pad 5 as a click pad. Unlike the touch pad 5, thetouch pad 6 does not sink. However, there may be a slight groove 6 a asillustrated in FIG. 4 or a level difference not illustrated in FIG. 4between the touch pad 6 and a side surface of the recessed portion 2 c.Because these obstacles (gaps) are also very small, no problem occurs atall when touch input is performed by a relatively thick finger F, butthe obstacles cause an erroneous operation described above when peninput is performed by using the pen tip of a relatively thin stylus S.In the following, description will be made with attention directed tothe touch pad 5. However, the present invention is similarly applicablealso to the touch pad 6.

Returning to FIG. 2 , the touch pad 5 includes a sensor 10 including aplurality of sensor electrodes 10 x and a plurality of sensor electrodes10 y, a sensor controller 11, a plurality of routing lines 12 x forconnecting each sensor electrode 10 x to the sensor controller 11, aplurality of routing lines 12 y for connecting each sensor electrode 10y to the sensor controller 11, and guard wiring LG for isolating each ofthe routing lines 12 x and 12 y from an external environment.

The sensor controller 11 is an integrated circuit configured to be ableto perform various processing operations. The processing operationsperformed by the sensor controller 11 includes processing of detectingpositions of the stylus S and the finger F within a panel surface of thetouch panel 5 a and receiving data transmitted by the stylus S, andoutputting the detected positions and the received data to the hostprocessor 7. In the present specification, this output may be referredto as a “report.” The sensor controller 11 and the host processor 7constitute a sensor system according to the present invention. Eachprocessing operation to be described later is performed by one of orboth the sensor controller 11 and the host processor 7.

The sensor controller 11 and the stylus S are configured to be able tocommunicate bidirectionally via the sensor 10. In the following, asignal transmitted by the sensor controller 11 to the stylus S will bereferred to as an “uplink signal,” and a signal transmitted by thestylus S to the sensor controller 11 will be referred to as a “downlinksignal.” Details of communication between the sensor controller 11 andthe stylus S will be described later in detail with reference to FIG. 5and FIGS. 6A and 6B.

As illustrated in FIG. 2 , the touch pad 5 includes an effective regionR1 and a detectable region R2. The effective region R1 is a regioncorresponding to the panel surface of the touch panel 5 a. On the otherhand, the detectable region R2 is a region outside the effective regionR1 in a region in which the sensor controller 11 can detect the stylusS. The detectable region R2 is disposed so as to enclose the effectiveregion R1.

In the following, processing performed by the sensor system according tothe present embodiment will be described in detail after description ofprocessing according to the background art.

FIG. 5 is a diagram illustrating processing performed by the sensorsystem according to the background art. The figure illustratesprocessing in which the sensor controller 11 pairs with a new stylus S,obtains the state, position, and the like of the stylus S, and reportsthe state, position, and the like of the stylus S to the host processor7. FIG. 6A is a diagram illustrating details of “state reportprocessing” performed in step S108 in FIG. 5 . FIG. 6B is a diagramillustrating details of “position etc. report processing” performed instep S111 in FIG. 5 .

First, the sensor controller 11 transmits an uplink signal via thesensor 10 (step S100). The sensor controller 11 periodically transmitsthe uplink signal, and performs a downlink signal receiving operationeach time the sensor controller 11 transmits the uplink signal (stepS101).

The sensor controller 11 determines whether or not a downlink signal isreceived as a result of the receiving operation performed in step S101(step S102). When the sensor controller 11 determines that no downlinksignal is received, the sensor controller 11 returns to step S100 torepeat the processing. When the sensor controller 11 determines that adownlink signal is received, on the other hand, the sensor controller 11performs pairing with the stylus S as a transmission source of thedownlink signal (step S103). Specifically, the sensor controller 11determines communication resources (a time slot, a frequency, a spreadcode, and the like) to be assigned to the stylus S and a localidentification (ID) to be assigned to the stylus S, and transmits anuplink signal indicating the communication resources and the local ID.The sensor controller 11 receives a pen ID from the stylus S by adownlink signal transmitted as a response to the uplink signal. When thepen ID can be thus received, the sensor controller 11 stores thereceived pen ID and information indicating the assigned communicationresources in association with the assigned local ID. Pairing issuccessful when the processing thus far is completed. The stylus Spairing with the sensor controller 11 stores the assigned communicationresources and the assigned local ID.

The sensor controller 11 determines whether or not the pairing with thestylus S has succeeded after step S103 is ended (step S104). When thesensor controller 11 determines that the pairing with the stylus S hasfailed, the sensor controller 11 returns to step S100 to repeat theprocessing. When the sensor controller 11 determines that the pairingwith the stylus S has succeeded, on the other hand, the sensorcontroller 11 makes an initial setting for processing to be described inthe following (step S105). Specifically, the sensor controller 11performs processing of setting a value of a pairing cancellation flag,to be described later, to an initial value False and the like.

The sensor controller 11 next transmits an uplink signal (step S106).The uplink signal can include the local ID assigned to the stylus Sbeing paired and a command signal indicating an instruction to thestylus S. Receiving the uplink signal, the stylus S transmits a downlinksignal at a timing determined on the basis of a reception timing of theuplink signal and the communication resources stored in advance. Inaddition, when the uplink signal includes the command signal includingthe local ID assigned to the stylus S itself, the stylus S performsprocessing indicated by the command signal.

The downlink signal includes a position signal for the sensor controller11 to detect the position of the stylus S and a pen pressure valueindicating a pressure applied to the pen tip of the stylus S. The stylusS includes a pressure sensor for detecting the pen pressure value. Thepen pressure value detected by the pressure sensor is zero when the pentip of the stylus S is not in contact with the panel surface. The penpressure value is a value larger than zero when the pen tip of thestylus S is in contact with the panel surface. In a case where thecommand signal requests transmission of specific data, the downlinksignal also includes the data.

The sensor controller 11 performs a downlink signal receiving operationat a timing at which the stylus S transmits the downlink signal (stepS107, a receiving step). Then, the sensor controller 11 first performsstate report processing (step S108).

The state report processing will be described with reference to FIG. 6A.Upon starting the state report processing, the sensor controller 11determines whether or not a downlink signal is received as a result ofperforming step S107, as illustrated in FIG. 6A (step S120). Whendetermining that a downlink signal is received, the sensor controller 11obtains a position (x, y) of the stylus S on the basis of a receptionstrength of a position signal in each of the plurality of sensorelectrodes 10 x and the plurality of sensor electrodes 10 y, and obtainsa pen pressure value P included in the downlink signal (step S121, anobtaining step). Then, the sensor controller 11 determines whether ornot a change in the pen pressure value P from zero to a value largerthan zero is detected (step S122). When the sensor controller 11determines that a change in the pen pressure value P from zero to avalue larger than zero is detected, the sensor controller 11 outputspen-down information indicating occurrence of a pen-down (contact of thestylus S with the panel surface of the touch panel 5 a) to the hostprocessor 7 in association with the local ID (step S123, a state outputstep). When the sensor controller 11 determines that a change in the penpressure value P from zero to a value larger than zero is not detected,the sensor controller 11 ends the state report processing.

The sensor controller 11 when determining in step S120 that no downlinksignal is received outputs pen-up information indicating occurrence of apen-up (detachment of the stylus S from the panel surface of the touchpanel 5 a) to the host processor 7 in association with the local ID(step S125, a state output step). The sensor controller 11 further setsa value of a pairing cancellation flag to True (step S126). The sensorcontroller 11 then ends the state report processing.

The description returns to FIG. 5 . Upon ending the state reportprocessing, the sensor controller 11 determines the value of the pairingcancellation flag (step S109). When the value of the pairingcancellation flag is True as a result, the sensor controller 11 cancelsthe pairing with the stylus S (step S110, a pairing canceling step).Specifically, the sensor controller 11 deletes the informationindicating the pen ID and the communication resources which informationis stored in association with the assigned local ID. The sensorcontroller 11 thereafter returns to step S100 to repeat the processing.When the sensor controller 11 determines in step S109 that the value ofthe pairing cancellation flag is False, on the other hand, the sensorcontroller 11 performs position etc. report processing (step S111), andthen returns the processing to step S106.

The position etc. report processing will be described with reference toFIG. 6B. Starting the position etc. report processing, the sensorcontroller 11 first determines whether or not the position (x, y)obtained in step S102 is a position within the effective region R1, asillustrated in FIG. 6B (step S130). When determining as a result thatthe position (x, y) is a position within the effective region R1, thesensor controller 11 outputs the position (x, y) and the pen pressurevalue P to the host processor 7 in association with the local ID (stepS131, a “position etc. output step” or an “output step” for short). Thesensor controller 11 then ends the processing. When determining that theposition (x, y) is not a position within the effective region R1, on theother hand, the sensor controller 11 obtains a position (correspondingposition) within the effective region R1 which position corresponds tothe position (x, y), and outputs the corresponding position to the hostprocessor 7 together with the local ID and the pen pressure value P(step S132).

FIG. 7 is a diagram of assistance in explaining the correspondingposition within the effective region R1. In the figure, a longitudinaldirection of the effective region R1 is set as an x-direction, and adirection orthogonal to the x-direction is set as a y-direction. Anx-coordinate of one end in the x-direction of the effective region R1,an x-coordinate of another end in the x-direction of the effectiveregion R1, a y-coordinate of one end in the y-direction of the effectiveregion R1, and a y-coordinate of another end in the y-direction of theeffective region R1 are set as x₀, x₁, y₀, and y₁, respectively.Further, an x-coordinate of another end in the x-direction (end portionon an x₁ side) of the detectable region R2 is set as x₂ (>x₁).

The sensor controller 11 compares the position x obtained in step S121with x₀ and x₁. When x is smaller than x₀ as a result, x is replacedwith x₀. When x is larger than x₁, x is replaced with x₁. In addition,the sensor controller 11 compares the position y obtained in step S121with y₀ and y₁. When y is smaller than y₀, y is replaced with y₀. When yis larger than y₁, y is replaced with y₁. The corresponding positionwithin the effective region R1, which corresponding position correspondsto the position (x, y), is a position obtained as a result of performingthe replacement processing.

FIG. 8 is a diagram illustrating a first example (comparative example1-1) of a result of performing the processing according to thebackground art as illustrated in FIG. 5 and FIGS. 6A and 6B. Times to t₀t₁₄ illustrated in the figure correspond to timings of transmission of adownlink signal by the stylus S. The stylus S according to the presentcomparative example approaches the panel surface of the touch panel 5 afrom above the effective region R1 between time to and time t₁, comesinto contact with the panel surface between times t₂ and t₃, thereaftermoves to the detectable region R2 between times t₅ and t₆ whilemaintaining the contact state, returns to the effective region R1between times t₁₀ and t₁₁, and thereafter separates from the panelsurface after the passage of time t₁₂. Positions x₀, x₁, x₂, y₀, and y₁illustrated in the figure are based on the example illustrated in FIG. 7.

When the stylus S approaches the panel surface, the sensor controller 11becomes able to obtain the position (x, y) and the pen pressure value Pat time t₁ after the above-described pairing. At this time point, thepen tip of the stylus S is not in contact with the panel surface yet,and therefore the pen pressure value P is zero. The stylus S is locatedabove the effective region R1, and therefore the detected position (x,y) satisfies x₀≤x≤x₁ and y₀≤y≤y₁.

When the pen tip of the stylus S thereafter comes into contact with theeffective region R1 between times t₂ and t₃, the pen pressure value Pchanges to a value larger than zero at time t₃. When the pen tip of thestylus S next moves to the detectable region R2 between times t₅ and t₆,the detected position (x, y) changes to a position within the detectableregion R2 at time t₆. FIG. 8 illustrates a case where the position xchanges to a value satisfying x₁≤x≤x₂. When the pen tip of the stylus Sthereafter returns to the effective region R1 again between times t₁₀and t₁₁, the detected position (x, y) returns to a position within theeffective region R1 at time t₁₁.

When the pen tip of the stylus S separates from the panel surfacebetween times t₁₂ and t₁₃, the pen pressure value P changes to zero attime t₁₃. When a distance between the stylus S and the panel surfacethen increases between times t₁₃ and t₁₄, the downlink signal does notreach the sensor 10 at time t₁₄, and the sensor controller 11 becomesunable to obtain the position (x, y) and the pen pressure value P.

During a period from time t₁ to time t₁₃ during which the position (x,y) and the pen pressure value P can be obtained, the position (x, y) andthe pen pressure value P continue to be output from the sensorcontroller 11 to the host processor 7 in association with the local ID.During a period from time t₆ to time t₁₀ during which the pen tip of thestylus S is within the detectable region R2, the coordinates of thecorresponding position within the effective region R1 are output inplace of the obtained position (x, y). In the present example, asillustrated in FIG. 8 , a position x₁ and y is output.

At time t₃ at which the pen pressure value P changes to a value largerthan zero, the sensor controller 11 outputs pen-down information to thehost processor 7. The sensor controller 11 outputs pen-up information tothe host processor 7 at time t₁₄ at which the downlink signal cannot bereceived.

Here, the host processor 7 according to the present embodiment isconfigured to determine the state of the stylus S on the basis of thepen pressure value P supplied from the sensor controller 11.Specifically, the host processor 7 determines that there is a state of apen-up when the pen pressure value P is zero, and the host processor 7determines that a pen-down has occurred when the pen pressure value Phas changed from zero to a value larger than zero. While the penpressure value P continues to be a value larger than zero, the hostprocessor 7 determines that there is a state of pen movement indicatingthat the stylus S is sliding on the panel surface. The state sodetermined is used by the host processor 7 for movement of a cursordisplayed on a screen, a tap operation, generation and drawing of strokedata, and the like.

The host processor 7 according to the present embodiment is configuredto end processing related to the stylus S when pen-up information issupplied from the sensor controller 11. Even when the same stylus S isthereafter used again, the host processor 7 performs processing such asstroke data generation, in a manner different from that of the previousprocessing.

FIG. 9 is a diagram illustrating a second example (comparative example1-2) of a result of performing the processing according to thebackground art as illustrated in FIG. 5 and FIGS. 6A and 6B. The presentcomparative example is different from the comparative example 1-1 inthat the stylus S passes the level difference 5 d illustrated in FIG. 3Bbetween times t₆ and t₉. The present comparative example is otherwisesimilar to the comparative example 1-1.

While the pen tip traverses over the level difference 5 d, the penpressure value P obtained by the sensor controller 11 is zero, andimmediately after the pen tip passes through (and leaves) the leveldifference 5 d, the pen pressure value P temporarily becomes a largevalue. The thus temporarily large value of the pen pressure value P iswritten as “P>>0” in FIG. 9 and the following figures.

Because the pen pressure value P changes from zero to a value largerthan zero at time t₉, the host processor 7 detects a pen-down at timet₉. This pen-down occurs due to the stylus S passing through theobstacle presented by the level difference 5 d, and is not intended bythe user. Also, the position supplied to the host processor 7 at time t₉is not an actual position of the pen tip of the stylus S (positionwithin the detectable region R2), but is substituted as thecorresponding position within the effective region R1. Hence, when anoperable graphical user interface (GUI). such as the “close” button, isdisplayed within the display 3 at a position that corresponds to acorresponding position within the effective region R1, an unintended tapoperation is triggered, which would then be recognized by the user as anerroneous (unintended) operation.

The sensor system according to the present embodiment preventsoccurrence of an erroneous operation as described above by concealingoccurrence of a pen-down from the host processor 7 when the obtainedposition (x, y) is outside the effective region R1. Processing performedby the sensor system according to the present embodiment for thatpurpose will be described in detail in the following.

FIG. 10 is a diagram illustrating position etc. report processingperformed by the sensor system according to the present embodiment. Asis understood from comparison of FIG. 10 with FIG. 6B, the position etc.report processing performed by the sensor system according to thepresent embodiment is different from the position etc. report processingperformed by the sensor system according to the background art in thatsteps S1 to S5 are added in the position etc. report processingperformed by the sensor system according to the present embodiment. Thefollowing description will be made centering on the differences.

As illustrated in FIG. 10 , the sensor system according to the presentembodiment sets a value of an output replacement flag to False afterperforming step S131 (step S1). The output replacement flag is avariable that becomes False when the sensor controller 11 reports thepen pressure value P obtained in step S121 in FIG. 6A “as is,” and whichbecomes True otherwise. An initial value of the output replacement flagis False, and an initial setting thereof is made in step S105 in FIG. 5.

The sensor system according to the present embodiment, when determiningin step S130 that the position (x, y) is not a position within theeffective region R1 (step S2), first determines whether or not the penpressure value P is zero. When determining that the pen pressure value Pis zero, the sensor system according to the present embodiment sets thevalue of the output replacement flag to True (step S3), and thereafteradvances the processing to step S4. When determining that the penpressure value P is not zero, the sensor system advances the processingto step S4 without changing the value of the output replacement flag.

In step S4, the sensor system determines the value of the outputreplacement flag (step S4). When determining as a result that the valueof the output replacement flag is False, the sensor system outputs thecorresponding position within the effective region R1 and the penpressure value P to the host processor 7 in association with the localID assigned during pairing (step S132). When determining that the valueof the output replacement flag is True, on the other hand, the sensorsystem limits (e.g., prevents) the output of the pen pressure value P.Specifically, the sensor system outputs the corresponding positionwithin the effective region R1 and a pen pressure value of zero (thatis, a pen pressure value indicating noncontact) to the host processor 7in association with the local ID assigned during pairing (step S5).Thus, when the pen tip of the stylus S is located outside the effectiveregion R1 and after the pen pressure value P becomes zero even once, thepen pressure value of zero is reported in place of the pen pressurevalue P until the pen tip of the stylus S returns to the effectiveregion R1.

FIG. 11 is a diagram illustrating an example (example 1-1) of a resultof performing the position etc. report processing illustrated in FIG. 10. Movements of the stylus S in the present example are identical tothose of the comparative example 1-2 illustrated in FIG. 9 . Adifference between the present example and the comparative example 1-2lies in that contents of data output to the host processor 7 by thesensor controller 11 in response to the movements of the stylus S aredifferent.

Specifically, during a period from time t₇ at which the pen pressurevalue P becomes zero till when the pen tip of the stylus S returns tothe effective region R1, during which the pen tip of the stylus S islocated outside the effective region R1, the pen pressure value P isoutput as is in the comparative example 1-2, whereas the pen pressurevalue of zero is output in the present example. Hence, the hostprocessor 7 is prevented from generating a pen-down in response to asharp rise in the pen pressure value P at time t₉.

As described above, the sensor system according to the presentembodiment can prevent generation of a pen-down against the user's willwhen the pen tip of the stylus S is located outside the effective regionR1. It is therefore possible to prevent the occurrence of an erroneousoperation caused by an obstacle such as a level difference or a groovepresent within the detectable region R2, such as the erroneous tappingof the “close” button displayed at an edge of the display 3 and thelike.

A few modifications of the present embodiment are conceivable. A firstmodification and a second modification of the present embodiment will bedescribed in the following with reference to drawings.

FIG. 12 is a diagram illustrating position etc. report processingperformed by a sensor system according to a first modification of thepresent embodiment. As is understood from comparison of FIG. 12 withFIG. 10 , the sensor system according to the present modification isdifferent from the sensor system according to the present embodiment inthat the sensor system according to the present modification limits(e.g., prevents) the output of the pen pressure value P by notperforming step S5. Because step S5 is not performed, when the penpressure value P once becomes zero while the pen tip of the stylus S islocated outside the effective region R1, the position (x, y) and the penpressure value P are thereafter not supplied to the host processor 7until the pen tip of the stylus S returns to the inside of the effectiveregion R1. Hence, as in the present embodiment, the host processor 7 isprevented from generating a pen-down in response to a sharp rise in thepen pressure value P at time t₉.

FIG. 13 is a diagram illustrating an example (example 1-2) of a resultof performing the position etc. report processing illustrated in FIG. 12. Movements of the stylus S in the present example are also identical tothose of the comparative example 1-2 illustrated in FIG. 9 . Asillustrated in FIG. 13 , in the present example, during a period fromtime t₇ at which the pen pressure value P becomes zero until when thepen tip of the stylus S returns to the effective region R1, during whichthe pen tip of the stylus S is located outside the effective region R1,the reporting of the position (x, y) and the pen pressure value P to thehost processor 7 is stopped. While the reporting is stopped, the hostprocessor 7 waits for the reporting to resume while maintaining thestate of the stylus S. After the reporting is resumed, the hostprocessor 7 resumes processing for movement of the cursor displayed onthe screen, generation and drawing of stroke data, and the like.

As described above, the sensor system according to the presentmodification also can prevent the occurrence of a pen-down when the pentip of the stylus S is located outside the effective region R1. Hence,as in the present embodiment, it is possible to prevent the occurrenceof an erroneous operation caused by an obstacle such as a leveldifference or a groove present within the detectable region R2, such asthe erroneous tapping of the “close” button displayed at an edge of thedisplay 3 and the like.

FIG. 14 is a diagram illustrating position etc. report processingperformed by a sensor system according to a second modification of thepresent embodiment. As is understood from comparison of FIG. 14 withFIG. 10 , the sensor system according to the present modification isdifferent from the sensor system according to the present embodiment inthat the sensor system according to the present modification performsstep S10 between step S131 and step S1, performs step S11 after stepS132, and performs step S12 in place of step S5.

Steps S10 and S11 are each a step of assigning the pen pressure value Pto a variable Pa. The variable Pa is a variable for temporarily storingthe pen pressure value P. An initial value of the variable Pa is zero,and an initial setting thereof is made in step S105 in FIG. 5 . Step S12is different from step S5 illustrated in FIG. 10 in that step S12 limits(e.g., prevents) the output of the pen pressure value P by outputting apen pressure value Pa (first value) in place of the pen pressure valueof zero. According to these processing operations, when the pen pressurevalue P once becomes zero while the pen tip of the stylus S is locatedoutside the effective region R1, the pen pressure value Pa (>0)immediately before the pen pressure value P becomes zero is thereafteroutput in place of a newly obtained pen pressure value P until the pentip of the stylus S returns to the inside of the effective region R1.Hence, as in the present embodiment, the host processor 7 is preventedfrom generating a pen-down in response to a sharp rise in the penpressure value P at time t₉.

FIG. 15 is a diagram illustrating an example (example 1-3) of a resultof performing the position etc. report processing illustrated in FIG. 14. Movements of the stylus S in the present example are also identical tothose of the comparative example 1-2 illustrated in FIG. 9 . Asillustrated in FIG. 15 , in the present example, during a period fromtime t₇ at which the pen pressure value P becomes zero till when the pentip of the stylus S returns to the effective region R1, during which thepen tip of the stylus S is located outside the effective region R1, thepen pressure value Pa is reported to the host processor 7 in place ofthe pen pressure value P. Hence, the pen pressure value P at time t₉which rises sharply due to an effect of an obstacle such as a leveldifference or a groove is not reported to the host processor 7.

As described above, the sensor system according to the presentmodification also can prevent the occurrence of a pen-down when the pentip of the stylus S is located outside the effective region R1. Hence,as in the present embodiment, it is possible to prevent the occurrenceof an erroneous operation caused by an obstacle such as a leveldifference or a groove present within the detectable region R2, such asthe erroneous tapping of the “close” button displayed at an edge of thedisplay 3 and the like.

In the present embodiment, as in a second embodiment to be describedlater, the output of a pen-down does not have to be performed when thepen tip of the stylus S is located outside the effective region R1. Thiscan prevent the occurrence of a pen-down when the pen tip of the stylusS is located outside the effective region R1 even if some application isperforming processing according to the pen state supplied from thesensor controller 11.

Second Embodiment

A sensor system according to the second embodiment of the presentinvention will next be described. The sensor system according to thepresent embodiment is different from the sensor system according to thefirst embodiment in terms of timing at which the sensor controller 11outputs a pen-up. In addition, processing performed by the hostprocessor 7 is also different from that described in the firstembodiment. The following description will be made with attentiondirected to these differences.

FIG. 16 is a diagram illustrating state report processing performed by asensor system according to the background art. The state reportprocessing illustrated in FIG. 16 is different from the state reportprocessing illustrated in FIG. 6A in that step S125 is not performed andin that steps S127 and S128 are added.

The sensor system according to the background art determines whether ornot a change in the pen pressure value P from a value larger than zeroto zero is detected (step S127) after the processing of steps S122 andS123 is ended. When it is determined that a change in the pen pressurevalue P from a value larger than zero to zero is detected, theabove-described pen-up information is output to the host processor 7 inassociation with the local ID (step S128, a state output step). When itis determined that no change in the pen pressure value P from a valuelarger than zero to zero is detected, the state report processing isended.

Unlike the host processor 7 according to the first embodiment, the hostprocessor 7 according to the present embodiment is configured to use thepen state (a pen-up or a pen-down) supplied from the sensor controller11 as the state of the stylus S. That is, the host processor 7 accordingto the present embodiment performs processing for movement of the cursordisplayed on the screen, a tap operation, generation and drawing ofstroke data, and the like, on the basis of the pen state supplied fromthe sensor controller 11.

FIG. 17 is a diagram illustrating a first example (comparative example2-1) of a result of performing the processing according to thebackground art as illustrated in FIG. 16 . Movements of the stylus Saccording to the present comparative example are similar to those of thecomparative example 1-1 illustrated in FIG. 8 . As illustrated in FIG.17 , in the present comparative example, pen-up information is reportedto the host processor 7 in response to the pen pressure value P becomingzero at time t₁₃. As a result, the state of the stylus S which isinternally possessed by the host processor 7 is the same as in thecomparative example 1-1 of FIG. 8 .

FIG. 18 is a diagram illustrating a second example (comparative example2-2) of a result of performing the processing according to thebackground art as illustrated in FIG. 16 . Movements of the stylus Saccording to the present comparative example are similar to those of thecomparative example 1-2 illustrated in FIG. 9 . As illustrated in FIG.18 , in the present comparative example, pen-up information is reportedto the host processor 7 at each of times t₇ and t₁₃. As a result, thestate of the stylus S which is internally possessed by the hostprocessor 7 is the same as in the comparative example 1-2 of FIG. 9 .

Here, the first embodiment prevents the occurrence of a pen-down whenthe pen tip of the stylus S is located outside the effective region R1by changing the output content of the pen pressure value P or stoppingthe output of the pen pressure value P. In the present embodiment, onthe other hand, the processing of the host processor 7 is different, andtherefore the occurrence of a pen-down when the pen tip of the stylus Sis located outside the effective region R1 cannot be prevented by thesame method as in the first embodiment. Accordingly, the sensor systemaccording to the present embodiment prevents the occurrence of apen-down when the pen tip of the stylus S is located outside theeffective region R1 by stopping the output of the pen state from thesensor controller 11. Description will be made in detail in thefollowing.

FIG. 19 is a diagram illustrating state report processing performed bythe sensor system according to the present embodiment. As is understoodfrom comparison of FIG. 19 with FIG. 16 , the state report processingperformed by the sensor system according to the present embodiment isdifferent from the state report processing performed by the sensorsystem according to the background art in that step S20 is added in thestate report processing performed by the sensor system according to thepresent embodiment.

Step S20 is a step of determining whether or not the position (x, y)obtained in step S121 is a position within the effective region R1. Whenthe sensor system according to the present embodiment determines in thestep S20 that the position (x, y) obtained in step S121 is a positionwithin the effective region R1, the sensor system performs theprocessing of steps S122 and S127 as in the sensor system according tothe background art. When the sensor system according to the presentembodiment determines that the position (x, y) obtained in step S121 isnot a position within the effective region R1, on the other hand, thesensor system skips the processing of steps S122 and S127. Thus, whenthe position (x, y) is not a position within the effective region R1,the pen state is not reported from the sensor controller 11 to the hostprocessor 7.

FIG. 20 is a diagram illustrating an example (example 2) of a result ofperforming the state report processing illustrated in FIG. 19 .Movements of the stylus S in the present example are identical to thoseof the comparative example 2-2 illustrated in FIG. 18 . A differencebetween the present example and the comparative example 2-2 lies in thatthe contents of the pen state output to the host processor 7 by thesensor controller 11 in response to the movements of the stylus S isdifferent.

Specifically, during a period from time t₆ to time t₁₀ during which thepen tip of the stylus S is located outside the effective region R1, apen-up and a pen-down are each output once in the comparative example2-2, whereas the pen-up and the pen-down are not output even once in thepresent example. This prevents an occurrence of an operation triggeredby a pen-down due to a sharp rise in the pen pressure value P at timet₉.

As described above, the sensor system according to the presentembodiment also can prevent the occurrence of a pen-down against theuser's will when the pen tip of the stylus S is located outside theeffective region R1. Hence, as in the first embodiment, it is possibleto prevent the occurrence of an erroneous operation caused by anobstacle such as a level difference or a groove present within thedetectable region R2, t such as the erroneous tapping of the “close”button displayed at an edge of the display 3 and the like.

Also in the present embodiment, as described in the first embodiment andthe first and second modifications thereof, processing such as changingthe output content of the pen pressure value P or stopping the output ofthe pen pressure value P may be performed when the pen tip is locatedoutside the effective region R1.

Third Embodiment

A sensor system according to a third embodiment of the present inventionwill next be described.

FIG. 21 is a diagram illustrating a tablet terminal 20 according to thepresent embodiment. The tablet terminal 20 is the above-described dualscreen model. The tablet terminal 20 has a configuration in which acasing 2 a having a display 3 a (first display) and a casing 2 b havinga display 3 b (second display) are connected to each other via a hinge21. The casing 2 b is configured to be rotatable 360 degrees along anarrow A illustrated in the figure about the hinge 21.

The displays 3 a and 3 b are each configured to support both pen inputand touch input. Pen input is realized when a user slides a pen tip of astylus S on the displays 3 a and 3 b, and sensor controllers 11 a and 11b (see FIG. 22 ) to be described later detect a trajectory of the pentip of the stylus S. Touch input is realized when the user slides afinger F of the user on the displays 3 a and 3 b, and the sensorcontrollers 11 a and 11 b (see FIG. 22 ) to be described later detect atrajectory of the finger F.

FIG. 22 is a diagram illustrating an internal configuration of thetablet terminal 20. FIG. 22 illustrates only parts related to pen inputand touch input in the displays 3 a and 3 b. As illustrated in FIG. 22 ,the tablet terminal 20 also includes a host processor 7. The hostprocessor 7 is a central processing unit that controls various parts ofthe tablet terminal 20. The host processor 7 plays a role of reading andexecuting programs stored in a memory not illustrated. The programsexecuted by the host processor 7 include an operating system of thetablet terminal 20, various kinds of drawing applications, various kindsof communication programs, and the like.

The display 3 a includes a sensor 10 a including a plurality of sensorelectrodes 10 xa and a plurality of sensor electrodes 10 ya, a sensorcontroller 11 a, a plurality of routing lines 12 xa for connecting eachsensor electrode 10 xa to the sensor controller 11 a, a plurality ofrouting lines 12 ya for connecting each sensor electrode 10 ya to thesensor controller 11 a, and guard wiring LG for isolating each of therouting lines 12 xa and 12 ya from an external environment. Similarly,the display 3 b includes a sensor 10 b including a plurality of sensorelectrodes 10 xb and a plurality of sensor electrodes 10 yb, a sensorcontroller 11 b, a plurality of routing lines 12 xb for connecting eachsensor electrode 10 xb to the sensor controller 11 b, a plurality ofrouting lines 12 yb for connecting each sensor electrode 10 yb to thesensor controller 11 b, and guard wiring LG for isolating each of therouting lines 12 xb and 12 yb from the external environment.

The routing lines 12 xa and 12 xb are each connected to an end portion,which is on a side farther from the hinge 21 illustrated in FIG. 21 ofthe two ends in the y-direction, of the corresponding sensor electrode10 xa or 10 xb. The routing lines 12 xa and 12 xb are configured in thismanner in order to make a distance between the screens of the displays 3a and 3 b as short as possible.

The sensor controllers 11 a and 11 b are each an integrated circuitconfigured to be able to perform various processing operations. Theprocessing operations performed by the sensor controllers 11 a and 11 binclude processing of detecting positions of the stylus S and the fingerF within panel surfaces of the displays 3 a and 3 b and receiving datatransmitted by the stylus S, and reporting the detected positions andthe received data to the host processor 7. The sensor controllers 11 aand 11 b and the host processor 7 constitute a sensor system accordingto the present invention. Each processing operation to be describedlater is performed by one or more of the sensor controllers 11 a and 11b and the host processor 7.

As with the sensor controller 11 according to the first embodiment, thesensor controllers 11 a and 11 b are each configured to be able tocommunicate bidirectionally with the stylus S via the sensors 10 a and10 b. In the following, signals transmitted by the sensor controllers 11a and 11 b to the stylus S will be referred to as “uplink signals,” andsignals transmitted by the stylus S to the sensor controllers 11 a and11 b will be referred to as “downlink signals.”

As illustrated in FIG. 22 , the display 3 a includes an effective regionR1 a and a detectable region R2 a. The effective region R1 a is a regioncorresponding to the panel surface of the display 3 a. The detectableregion R2 a is a region outside the effective region R1 a in a region inwhich the sensor controller 11 a can detect the stylus S. The detectableregion R2 a is disposed so as to enclose the effective region R1 a.

Similarly, the display 3 b includes an effective region R1 b and adetectable region R2 b. The effective region R1 b is a regioncorresponding to the panel surface of the display 3 b. The detectableregion R2 b is a region outside the effective region R1 b in a region inwhich the sensor controller 11 b can detect the stylus S. The detectableregion R2 b is disposed so as to enclose the effective region R1 b.

A non-sensitive region R3 that cannot detect the stylus S is formedbetween the detectable region R2 a and the detectable region R2 b. Whenthe pen tip of the stylus S is present within the non-sensitive regionR3, neither of the sensor controllers 11 a and 11 b can receive adownlink signal from the stylus S.

Processing performed by the sensor system according to the backgroundart is similar to the processing described with reference to FIG. 5 andFIGS. 6A and 6B. The sensor controllers 11 a and 11 b and the hostprocessor 7 according to the background art are configured to treat thedisplays 3 a and 3 b as one touch surface, by communicating with eachother as needed. Specifically, information regarding the stylus S pairedwith one of the sensor controllers 11 a and 11 b is configured to beshareable by the other of the sensor controllers 11 a and 11 b.

In addition, as in the first embodiment, the host processor 7 accordingto the present embodiment is configured to determine the state of thestylus S on the basis of the pen pressure value P supplied from thesensor controllers 11 a and 11 b, and to end the processing related tothe stylus S when pen-up information is reported from the sensorcontrollers 11 a and 11 b.

FIG. 23 is a diagram explaining potential problems that can be solved bythe present embodiment. FIG. 23 illustrates a case where a surface ofthe casing 2 b is disposed at a position of 180 degrees relative to asurface of the casing 2 a (see FIG. 21 ). Stroke data ST illustrated inthe FIG. 23 is an example of stroke data that a user of the tabletterminal 20 may desire to draw. The stroke data ST constitutes onecontinuous line drawing that straddles the displays 3 a and 3 b. Withthe sensor system according to the background art, even when such strokedata ST is to be drawn by using the stylus S, a pen-up not intended bythe user may occur between the displays 3 a and 3 b (for example due toa level difference or a small groove) and pairing may be canceled, andas a result the stroke data ST may become two different stroke data forthe respective displays 3 a and 3 b (as opposed to one stroke datastraddling the displays 3 a and 3 b as shown in FIG. 23 ). Specifically,this is due to the presence of an obstacle, such as a level differenceor a groove between the displays 3 a and 3 b, and the presence of thenon-sensitive region R3. Hence, an aspect of the sensor system accordingto the present embodiment is to prevent the occurrence of a pen-up notintended by the user between the displays 3 a and 3 b and prevent thecancellation of pairing, and thereby enable the drawing of one strokedata straddling the displays 3 a and 3 b, such as the stroke data ST(one stroke data) illustrated in FIG. 23 .

FIG. 23 also illustrates coordinates to be used in the followingdescription. As illustrated in FIG. 23 , in the following description,an arrangement direction of the effective regions R1 a and R1 b is setas a y-direction, and a direction orthogonal to the y-direction is setas an x-direction. An x-coordinate of one end in the x-direction of theeffective region R1 a and an x-coordinate of another end in thex-direction of the effective region R1 a are set as x₀ and x₁,respectively. In this case, an x-coordinate of one end in thex-direction of the effective region R1 b and an x-coordinate of anotherend in the x-direction of the effective region R1 b are also x₀ and x₁,respectively. Further, a y-coordinate of one end in the y-direction ofthe effective region R1 a, a y-coordinate of another end in they-direction of the effective region R1 a, a y-coordinate of another endin the y-direction of the detectable region R2 a (end portion on theeffective region R1 b side), a y-coordinate of one end in they-direction of the detectable region R2 b (end portion on the effectiveregion R1 a side), a y-coordinate of one end in the y-direction of theeffective region R1 b, and a y-coordinate of another end in they-direction of the effective region R1 b are set as y₀, y₁, y₂, y₃, y₄,and y₅, respectively.

In the following description, a region satisfying y₁≤y≤y₂ in thedetectable region R2 a may be particularly referred to as a specificdetectable region R2 aa, and a region satisfying y₃≤y≤y₄ in thedetectable region R2 b may be particularly referred to as a specificdetectable region R2 ba. In FIG. 23 , these specific detectable regionsR2 aa and R2 ba are indicated clearly by hatching.

FIG. 24 is a diagram illustrating an example (comparative example 3) ofa result of performing processing according to the background art. Timest₀ to t₁₇ illustrated in FIG. 24 correspond to timings of transmissionof a downlink signal by the stylus S. The stylus S according to thepresent comparative example approaches the display 3 a from above theeffective region R1 a between time t₀ and time t₁, comes into contactwith the panel surface of the display 3 a between times t₂ and t₃, andthereafter moves to the specific detectable region R2 aa between timest₅ and t₆ while maintaining the contact state. Then, the stylus Ssequentially moves to the non-sensitive region R3 between times t₈ andt₉, to the specific detectable region R2 ba between times t₁₀ and t₁₁,and to the effective region R1 b between times t₁₃ and t₁₄, andseparates from the panel surface of the display 3 b after the passage oftime t₁₅.

As illustrated in FIG. 24 , when the stylus S approaches the display 3a, the sensor controller 11 a becomes able to obtain the position (x, y)and the pen pressure value P at time t₁ after the above-describedpairing. At this time point, the pen tip of the stylus S is not incontact with the panel surface yet, and therefore the pen pressure valueP is zero. In addition, the stylus S is located above the effectiveregion R1 a, and therefore the detected position (x, y) satisfiesx₀≤x≤x₁ and y₀≤y≤y₁.

When the pen tip of the stylus S thereafter comes into contact with theeffective region R1 a between times t₂ and t₃, the pen pressure value Pchanges to a value larger than zero at time t₃. When the pen tip of thestylus S next moves to the specific detectable region R2 aa betweentimes t₅ and t₆, the detected position (x, y) changes to a positionwithin the specific detectable region R2 aa at time t₆.

FIG. 24 illustrates a case where there is an obstacle such as a leveldifference or a groove within the specific detectable region R2 aa. Dueto effects of this obstacle, the pen pressure value P temporarilybecomes zero at time t₇, and the pen pressure value P temporarilybecomes a large value at time t₈.

When the pen tip of the stylus S moves to the non-sensitive region R3between times t₈ and t₉, neither of the sensor controllers 11 a and 11 bcan receive a downlink signal from the stylus S, and therefore none ofthe position (x, y) and the pen pressure value P are detected. Thus,pairing with the stylus S is temporarily canceled in step S110 in FIG. 5.

When the pen tip of the stylus S thereafter enters the specificdetectable region R2 ba between times t₁₀ and t₁₁, pairing is performedagain, and the detected position (x, y) changes to a position within thespecific detectable region R2 ba at time t₁₁. Further, when the pen tipof the stylus S enters the effective region R1 b between times t₁₃ andt₁₄, the detected position (x, y) changes to a position within theeffective region R1 b at time t₁₄. FIG. 23 illustrates a case wherethere is no obstacle such as a level difference or a groove within thespecific detectable region R2 ba. However, needless to say, there is apossibility of the presence of an obstacle such as a level difference ora groove within the specific detectable region R2 ba. In that case,changes in the pen pressure value P that are similar to those at timest₇ and t₈ are observed.

When the pen tip of the stylus S separates from the panel surfacebetween times t₁₅ and t₁₆, the pen pressure value P changes to zero attime t₁₆. When a distance between the stylus S and the panel surfacethen increases between times t₁₆ and t₁₇, the downlink signal does notreach the sensor 10 b at time t₁₇, and the sensor controller 11 bbecomes unable to obtain the position (x, y) and the pen pressure valueP again.

During a period from time t₁ to time t₈, the sensor controller 11 aoutputs the position (x, y) and the pen pressure value P to the hostprocessor 7 in association with a first local ID (written as “LID1” inFIG. 24 and the following figures). In addition, during a period fromtime t₁₁ to time t₁₆, the sensor controller 11 b outputs the position(x, y) and the pen pressure value P to the host processor 7 inassociation with a second local ID (written as “LID2” in FIG. 24 and thefollowing figures). However, during a period from time t₆ to time t₈ anda period from time t₁₁ to time t₁₃ during which the pen tip of thestylus S is located within the detectable region R2 a or R2 b, thecorresponding position (the position y₁ or the position y₄) within theeffective region is output in place of the obtained position y.

The host processor 7 determines that a pen-down has occurred on thebasis of changes in the pen pressure value P to a value larger than zeroat times t₃, t₈, and t₁₁. The host processor 7 determines that thestylus S is in the state of a pen-up at times t₁, t₂, t₇, and t₁₆ atwhich the pen pressure value P is zero. The sensor controllers 11 a and11 b report pen-up information at times t₉ and t₁₇ at which the downlinksignal becomes unable to be received. The host processor 7 thereby endsthe processing related to the stylus S at each of times t₉ and t₁₇.

The pen-up occurring at time t₇ as well as pairing cancellation and theending of the processing related to the stylus S in the host processor 7at time t₉ are not intended by the user trying to draw the stroke dataST illustrated in FIG. 23 . As a result, the line drawing intended bythe user is broken against the user's will.

The sensor system according to the present embodiment prevents the linedrawing from being broken as described above, by concealing theoccurrence of a pen-up from the host processor 7 and delaying pairingcancellation when the obtained position (x, y) is outside the effectiveregion R1. Processing performed by the sensor system according to thepresent embodiment for that purpose will be described in detail in thefollowing.

FIG. 25 is a diagram illustrating state report processing performed bythe sensor system according to the present embodiment. As is understoodfrom comparison of FIG. 25 with FIG. 6A, the state report processingperformed by the sensor system according to the present embodiment isdifferent from the state report processing performed by the sensorsystem according to the background art in that steps S30 to S34 areadded in the state report processing performed by the sensor systemaccording to the present embodiment. The following description will bemade centering on the differences.

As illustrated in FIG. 25 , when the sensor system according to thepresent embodiment determines in step S120 that the downlink signalcannot be received, the sensor system first determines whether or notthe pen tip of the stylus S is located in a region between the screensof the display 3 a and the display 3 b (between panel surfaces) (stepS30, a determining step). It suffices for the sensor system to make aresult of the determination in step S30 positive when the last obtainedposition (x, y) is located in one of the specific detectable regions R2aa and R2 ba, and make the result of the determination in step S30negative otherwise.

Upon obtaining a negative result in step S30, the sensor system performssteps S125 and S126 described with reference to FIG. 6A, and then endsthe state report processing. Consequently, pairing with the stylus S iscanceled in step S110 in FIG. 5 .

Upon obtaining a positive result in step S30, on the other hand, thesensor system determines whether or not a variable N is larger than apredetermined value K (step S31). An initial value of the variable N iszero, and an initial setting thereof is made in step S105 in FIG. 5 .When determining in step S31 that the variable N is larger than thepredetermined value K, the sensor system performs steps S125 and S126,and then ends the state report processing. Consequently, pairing withthe stylus S is canceled in step S110 in FIG. 5 . When determining instep S31 that the variable N is not larger than the predetermined valueK, on the other hand, the sensor system increments the variable N by one(step S32). As a result of these processing operations, the output ofpen-up information and pairing cancellation are delayed for apredetermined period defined by the predetermined value K.

The sensor system may end the state report processing immediately afterending step S32. However, as indicated by a broken line in FIG. 25 , thesensor system may also output the position (x, y) and the pen pressurevalue P to the host processor 7 in association with the local ID on thebasis of the same values as the previous time (step S33, a previousvalue output step). This makes it possible to continue to output a validposition (x, y) and a valid pen pressure value P to the host processor 7even when the pen tip of the stylus S is located within thenon-sensitive region R3.

In addition, when the sensor system according to the present embodimentdetermines in step S120 that a downlink signal is received, the sensorsystem obtains the position (x, y) and the pen pressure value Pin stepS121, and assigns zero to the above-described variable N (step S34). Thesensor system thereafter performs the processing of steps S122 and S123as in FIG. 6A, and then ends the state report processing.

FIG. 26 is a diagram illustrating position etc. report processingperformed by the sensor system according to the present embodiment. Asis understood from comparison of FIG. 26 with FIG. 14 , the positionetc. report processing performed by the sensor system according to thepresent embodiment is obtained by adding steps S40 to S44 to theposition etc. report processing according to the second modification ofthe first embodiment as illustrated in FIG. 14 . The followingdescription will be made centering on the differences from FIG. 14 .

The sensor system according to the present embodiment determines whetheror not the pen tip of the stylus S is located in a region between thescreens of the display 3 a and the display 3 b (between the panelsurfaces) after performing the processing of steps S2 and S3 (step S40).This is processing similar to step S30 illustrated in FIG. 25 .

When obtaining a negative result in step S40, the sensor system performsthe processing of steps S4, S132, S11, and S12 as in FIG. 14 . Whenobtaining a positive result in step S40, on the other hand, the sensorsystem first determines the value of the output replacement flag (stepS41). When determining as a result that the value of the outputreplacement flag is False, the sensor system outputs the position (x, y)and the pen pressure value P to the host processor 7 in association withthe local ID assigned during pairing (step S42). Then, the sensor systemassigns the pen pressure value P to the variable Pa (step S43), and endsthe position etc. report processing. When determining that the value ofthe output replacement flag is True, on the other hand, the sensorsystem outputs the position (x, y) and the pen pressure value Pa to thehost processor 7 in association with the local ID assigned duringpairing (step S44).

According to the above processing, when the pen tip of the stylus S ispresent in a region that is outside the effective regions R1 a and R1 band is also outside the specific detectable regions R2 aa and R2 ba, asin the second modification of the first embodiment, the correspondingposition within the effective region R1 a or R1 b and the pen pressurevalue P are output until the pen pressure value P becomes zero, and whenthe pen pressure value P once becomes zero, the pen pressure value Pa(>0) immediately before the pen pressure value P becomes zero isthereafter output in place of a newly obtained pen pressure value Ptogether with the corresponding position within the effective region R1a or R1 b. When the pen tip of the stylus S is present within thespecific detectable region R2 aa or R2 ba, on the other hand, similarprocessing to the above is performed for the pen pressure value, whereasthe position (x, y) obtained in step S121 in FIG. 25 rather than thecorresponding position within the effective region R1 a or R1 b isoutput.

FIG. 27 is a diagram illustrating an example (example 3) of a result ofperforming the processing according to the present embodiment asillustrated in FIG. 25 and FIG. 26 . Movements of the stylus S in thepresent example are identical to those of the comparative example 3illustrated in FIG. 24 . As illustrated in FIG. 27 , in the presentexample, pen-up information is not output nor is pairing canceled attimes t₉ and t₁₀ at which the pen tip of the stylus S is located withinthe non-sensitive region R3. After time t₇ at which the pen pressurevalue P once becomes zero during a period from time t₆ to time t₁₃during which the pen tip of the stylus S is located outside theeffective regions R1 a and R1 b, the pen pressure value Pa (equal to thepen pressure value P at time t₆) is supplied to the host processor 7 inplace of the pen pressure value P. Hence, at time t₉, pairing is notcanceled, nor is the processing related to the stylus S in the hostprocessor 7 temporarily ended. Also, the host processor 7 does notgenerate a pen-up at time t₇. Thus, the stroke data ST illustrated inFIG. 23 is prevented from being broken between the displays 3 a and 3 b.

In addition, according to the present embodiment, during a period fromtime t₆ to time t₈ during which the pen tip of the stylus S is locatedwithin the specific detectable region R2 aa and during a period fromtime t₁₁ to time t₁₃ during which the pen tip of the stylus S is locatedin the specific detectable region R2 ba, coordinates within the specificdetectable regions R2 aa and R2 ba rather than the correspondingpositions within the effective regions R1 a and R1 b are supplied to thehost processor 7. The host processor 7 can therefore smoothly generatestroke data straddling the displays 3 a and 3 b. According to thepresent embodiment, during a period from time t₉ to time t₁₀ duringwhich the pen tip of the stylus S is located within the non-sensitiveregion R3, the position (x, y) and the pen pressure value P can continuebeing output in association with the local ID on the basis of the samevalues as the previous time. Consequently, the host processor 7 cangenerate the stroke data straddling the displays 3 a and 3 b moresmoothly.

As described above, with the sensor system according to the presentembodiment, no pen-up occurs and pairing is not canceled when the pentip of the stylus S is located between the screens. Thus, one line canbe drawn so as to straddle the displays 3 a and 3 b. In addition, whilethe pen tip of the stylus S is located within the specific detectableregions R2 aa and R2 ba, coordinates within the specific detectableregions R2 aa and R2 ba rather than the corresponding positions withinthe effective regions R1 a and R1 b are supplied to the host processor7, and while the pen tip of the stylus S is located within thenon-sensitive region R3, the position (x, y) and the pen pressure valueP can continue being output. It is therefore possible to generate thestroke data straddling the displays 3 a and 3 b smoothly.

In addition, with the sensor system according to the present embodiment,as for a region other than between the screens, as in the firstembodiment and the like, a pen-down can be prevented from occurringagainst the user's will when the pen tip of the stylus S is locatedoutside the effective region R1. It is therefore possible to prevent theoccurrence of an erroneous operation caused by an obstacle such as alevel difference or a groove present within the detectable regions R2 aand R2 b, such as an erroneous tapping of the “close” button displayedat edges of the displays 3 a and 3 b and the like.

While the pen pressure value Pa is output in steps S44 and S12 in FIG.26 in the present embodiment, the pen pressure value of zero may beoutput as in the first embodiment, or the pen pressure value need not beoutput as in the first modification of the first embodiment.

Fourth Embodiment

A sensor system according to a fourth embodiment of the presentinvention will next be described. The sensor system according to thepresent embodiment is different from the sensor system according to thethird embodiment in terms of timing at which the sensor controller 11outputs pen-up information. In addition, processing performed by thehost processor 7 is also different from that described in the thirdembodiment. The following description will be made with attentiondirected to the differences.

Processing performed by a sensor system according to the background artin relation to the present embodiment is identical to the processingperformed by the sensor system according to the background art inrelation to the second embodiment as described with reference to FIG. 16. As with the host processor 7 according to the second embodiment, thehost processor 7 according to the present embodiment is configured touse the pen state (a pen-up or a pen-down) reported from the sensorcontrollers 11 a and 11 b as the state of the stylus S.

FIG. 28 is a diagram illustrating an example (comparative example 4) ofa result of performing the processing according to the background art inrelation to the present embodiment. Movements of the stylus S accordingto the present comparative example are similar to those of thecomparative example 3 illustrated in FIG. 24 . As illustrated in FIG. 28, in the present comparative example, pen-up information is reportedfrom the sensor controller 11 a to the host processor 7 in response tothe pen pressure value P becoming zero at times t₇ and t₁₆. As a result,the state of the stylus S which is internally possessed by the hostprocessor 7 is the same as in the comparative example 3 of FIG. 24 .

The host processor 7 is configured to end the processing related to thestylus S after waiting for a certain time rather than immediately endingthe processing related to the stylus S while the position (x, y) and thelike are not supplied from the sensor controllers 11 a and 11 b at timest₉ and t₁₀. However, in the present comparative example, pairing is oncecanceled at time t₉, and as a result, the position (x, y) and the likesupplied at and after time t₁₁ are associated with a local ID differentfrom a local ID thus far. Thus, the host processor 7 processes strokedata up to time t₈, and stroke data at and after time t₁₁, as strokedata drawn by different styluses S.

Here, the third embodiment prevents the occurrence of a pen-up when thepen tip of the stylus S is located between the screens by changing theoutput content of the pen pressure value P or stopping the output of thepen pressure value P. Because the processing of the host processor 7 isdifferent in the present embodiment, the occurrence of a pen-up when thepen tip of the stylus S is located between the screens cannot beprevented by the same method as in the third embodiment. Accordingly,the sensor system according to the present embodiment prevents theoccurrence of a pen-down when the pen tip is located outside theeffective regions R1 a and R1 b by stopping the output of the pen statefrom the sensor controllers 11 a and 11 b. On the other hand, theprocessing of delaying pairing cancellation for a certain time when thepen tip of the stylus S is located between the screens is performed in asimilar manner to the third embodiment. Description will be made indetail in the following.

FIG. 29 is a diagram illustrating state report processing performed bythe sensor system according to the present embodiment. As is understoodfrom comparison of FIG. 29 with FIG. 25 , processing after it isdetermined in step S120 that no downlink signal is received is similarto the processing illustrated in FIG. 25 except that step S125, whichoutputs pen-up information, is not included. In addition, after it isdetermined in step S120 that a downlink signal is received, step S34 isperformed together with step S121, as in FIG. 25 . Hence, with thesensor system according to the present embodiment, the execution ofpairing cancellation is delayed by an amount corresponding to the numberof times defined by the predetermined value K.

In addition, as is understood from comparison of FIG. 29 with FIG. 19 ,processing after step S34 is similar to the processing of the sensorsystem according to the second embodiment as illustrated in FIG. 19 .Hence, with the sensor system according to the present embodiment, whenthe position (x, y) is not a position within the effective region R1 aor R1 b, the pen state is not reported from the sensor controllers 11 aand 11 b to the host processor 7.

FIG. 30 is a diagram illustrating position etc. report processingperformed by the sensor system according to the present embodiment. Asis understood from comparison of FIG. 30 with FIG. 6B, the position etc.report processing performed by the sensor system according to thepresent embodiment is obtained by adding step S50 to the processing ofFIG. 6B.

As with step S30 illustrated in FIG. 25 and step S40 illustrated in FIG.26 , step S50 is the processing of determining whether or not the pentip of the stylus S is located in a region between the screens of thedisplay 3 a and the display 3 b (between the panel surfaces). The sensorsystem according to the present embodiment makes the determination ofstep S50 when determining in step S130 that the position (x, y) is not aposition within the effective region R1 a or R1 b. Then, when the sensorsystem determines in step S50 that the pen tip of the stylus S islocated between the screens, the sensor system performs the processingof step S131. When the sensor system determines in step S50 that the pentip of the stylus S is not located between the screens, the sensorsystem performs the processing of step S132. Thus, when the pen tip ofthe stylus S is located between the screens, the processing of replacingthe position (x, y) with the corresponding position within the effectiveregion R1 a or R1 b is not performed.

FIG. 31 is a diagram illustrating an example (example 4) of a result ofperforming the processing according to the present embodiment asillustrated in FIG. 29 and FIG. 30 . Movements of the stylus S in thepresent example are identical to those of the comparative example 4illustrated in FIG. 28 . As illustrated in FIG. 31 , according to thepresent embodiment, the pen state is not output from the sensorcontrollers 11 a and 11 b to the host processor 7 during a period fromtime t₆ to time t₁₃ during which the pen tip of the stylus S is locatedoutside the effective regions R1 a and R1 b. In addition, pairing is notcanceled even at times t₉ and t₁₀ at which the pen tip of the stylus Sis located within the non-sensitive region R3. The local ID is thereforemaintained after the passage of time t₁₀. Hence, the host processor 7maintains the state of pen movement during a period from time t₆ to timet₁₃. The stroke data ST illustrated in FIG. 23 is therefore preventedfrom being broken between the displays 3 a and 3 b.

As described above, the sensor system according to the presentembodiment also does not generate a pen-up and does not cancel pairingwhen the pen tip of the stylus S is located between the screens. It istherefore possible to draw one line that straddles the displays 3 a and3 b.

The sensor system according to the present embodiment also can supplythe host processor 7 with coordinates within the specific detectableregions R2 aa and R2 ba rather than the corresponding positions withinthe effective regions R1 a and R1 b while the pen tip of the stylus S islocated within the specific detectable regions R2 aa and R2 ba, and alsocontinue outputting the position (x, y) and the pen pressure value Pwhile the pen tip of the stylus S is located within the non-sensitiveregion R3. The stroke data straddling the displays 3 a and 3 b cantherefore be generated smoothly.

Also with the sensor system according to the present embodiment, as fora region other than between the screens, as in the second embodiment andthe like, a pen-down can be prevented from occurring against the user'swill when the pen tip of the stylus S is located outside the effectiveregion R1. It is therefore possible to prevent the occurrence of anerroneous operation caused by an obstacle such as a level difference ora groove present within the detectable regions R2 a and R2 b, such as anerroneous tapping of the “close” button displayed at edges of thedisplays 3 a and 3 b and the like.

Also in the present embodiment, as described in the third embodiment,processing such as changing the output content of the pen pressure valueP or stopping the output of the pen pressure value P may be performedwhen the pen tip is located outside the effective regions R1 a and R1 b.

Preferred embodiments of the present invention have been describedabove. However, the present invention is not limited to suchembodiments, and the present invention can be carried out in variousmodes without departing from the spirit of the present invention.

The invention claimed is:
 1. A sensor system that detects a pointer on afirst panel surface of a first display having a first effective regionand a second panel surface of a second display having a second effectiveregion, the sensor system comprising: a memory device includingcomputer-executable instructions; and a processor which, when loadedwith the computer-executable instructions, performs: obtaining aposition of the pointer; outputting the obtained position to a hostprocessor; wherein the first effective region has a first sideinterfacing a side of the second effective region and has a second sidethat does not interface the side of the second effective region, inresponse to the obtained position being outside the first side of thefirst effective region, concealing from the host processor firstinformation indicating the pointer being removed from the first panelsurface, and in response to the obtained position being outside thesecond side of the first effective region, outputting the firstinformation to the host processor.
 2. The sensor system according toclaim 1, wherein the processor performs: in response to the obtainedposition being outside the first side of the first effective region, notoutputting the first information to the host processor for a definedperiod of time.
 3. The sensor system according to claim 1, wherein theprocessor performs: in response to the obtained position being outsidethe first side of the first effective region, outputting a replacementposition within the first effective region or the second effectiveregion corresponding to the obtained position to the host processor inplace of the obtained position.
 4. A sensor system that detects apointer on a first panel surface of a first display having a firsteffective region and a second panel surface of a second display having asecond effective region, the sensor system comprising: a memory deviceincluding computer-executable instructions; and a processor which, whenloaded with the computer-executable instructions, performs: obtaining aposition of the pointer; outputting the obtained position to a hostprocessor; wherein the first effective region has a first sideinterfacing a side of the second effective region and has a second sidethat does not interface the side of the second effective region, whereinthe processor, in response to the pointer leaving the first panelsurface, outputs a first notification to the host processor, wherein theoutput of the first notification is suppressed more strongly when thepointer crosses the first side than when the pointer crosses the secondside to leave the first panel surface.
 5. The sensor system according toclaim 4, wherein the processor performs: in response to the obtainedposition being outside the first side of the first effective region, notoutputting the first information to the host processor for a definedperiod of time.
 6. The sensor system according to claim 4, wherein theprocessor performs: in response to the obtained position being outsidethe first side of the first effective region, outputting a replacementposition within the first effective region or the second effectiveregion corresponding to the obtained position to the host processor inplace of the obtained position.
 7. A method of controlling a dual-screensensor system, wherein the system is configured to detect a pointer on afirst panel surface of a first display having a first effective regionand a second panel surface of a second display having a second effectiveregion, the method comprising: obtaining a position of the pointer;outputting the obtained position to a host processor; wherein the firsteffective region has a first side interfacing a side of the secondeffective region and has a second side that does not interface the sideof the second effective region, in response to the obtained positionbeing outside the first side of the first effective region, concealingfrom the host processor first information indicating the pointer beingremoved from the first panel surface, and in response to the obtainedposition being outside the second side of the first effective region,outputting the first information to the host processor.
 8. The methodaccording to claim 7, comprising: in response to the obtained positionbeing outside the first side of the first effective region, notoutputting the first information to the host processor for a definedperiod of time.
 9. The method according to claim 7, comprising: inresponse to the obtained position being outside the first side of thefirst effective region, outputting a replacement position within thefirst effective region or the second effective region corresponding tothe obtained position to the host processor in place of the obtainedposition.